Manufacture of explosives



1938- w. A. P. CHALLENOR ET AL 7 MANUFACTURE OF EXPLOSIVES Filed Oct.14, 1936 g 5 mil/m7? APCiza/lenor rdon 1 5 9! NTOR Edi ATTORNEY PatentedDec. 20,1938

, MANUFACE or, mmslvas William Arthur Percival Chalienor, and GordonAldridge Scott, West Kilbri Scotland, assignors to Imperial ChemicalIndustries Limited, a. corporation of' Great Britain Application October14, 1936, Serial No. 185,608

' In Great Britain October 21, 1935 4Claims.

The present invention relates to an improved method and apparatus fortransferring liquid explosives and particularly liquid nitric esterssuch as nitroglycerin in the form of an emulsion from one place toanother.

In the manufacture of nitroglycerin and similar liquid nitric esters itis customary to separate the liquid nitric ester from the refusenitrating acid and then to wash the separated liquid nitric ester byagitation with water and usually further with a dilute alkaline solutionbefore the liquid nitric ester is removed from theseparating house tothe final washing house in which it is further washed. The partly washednitric ester is sometimes run to the final washhouse along a gutter.

Should a detonation occur in the gutter in which the liquid nitric esteris flowing, or in one house connected thereto, it may be propagatedalong the liquid nitric ester flowing in the gutter, which may'thuscommunicate a detonation from one house to another.

In order to avoid the propagation of a detonation through the liquidnitric ester during its transport, it has been proposed to transport theliquid nitric ester in the form of an aqueous emulsion in which it isdispersed in acontinuous aqueous phase. Aqueous emulsions of liquidnitric esters, however, separate easily, and trouble may be experiencedin this respect, if the emulsion is transferred over any considerabledistance.

The present invention provides an improved method of transferring liquidexplosives, and particularly liquid nitric esters, in the form of anaqueous emulsion whereby the emulsion may be transferred overconsiderable distances without separating and with a reduced danger ofpropagation in the event of local detonation.

The chief object of the present invention is a new and improved 'methodof transferring liquid explosive material, and particularly liquidnitric esters. A further object is a method for transferring liquidexplosive material in the form of an aqueous emulsion. Another object isan apparatus for transferring the foregoing materials. An additionalobject is an improved method of transferring liquid explosive materialover considerable distances with reduced danger of propagation in theevent of local detonation.

Thus, for example, into a current of an emulsion of the liquid explosivein an aqueous medium there is introduced a stream of air at a volumetricspeed exceeding that of the emulsion so as to cause turbulence therein;the air being retained in association with the emulsion during itstravel through a long horizontal or somewhat inclined transfer tube, thediameter of which is sufiiciently narrow to cause the formation of aseries of short surges'in the emulsion which move 5 along the tube andare of suflicient size to occupy its cross section, and a plurality ofspaces occupied mainly by air, whereby the emulsion is prevented fromseparating out. The aqueous liquid used in making the emulsion may befor may be introduced into the feed vessel and part into the tube nearthe feed end. The transfer tube may leave the feed vessel horizontallyor at a slight inclination, but if desired a portion at the feed end ofthe transfer tube may be bent over into a substantially verticaldirection and arranged so as to "form a short air lift portion.

The emulsion is introduced under a pressure sumcient to drive theemulsion and air through the transfer tube. The air may conveniently besupplied from a reducing valve on a high pressure air line, and afterstarting up the supply of air the emulsion maybe admitted, and the airsupply adjusted to cause the development of alternate surges and spaces.When it is no longer desired to transfer emulsion, a quantity of watermay be introduced into the system and the air supply may be continuedfor some time.

By way of illustration it may be said that with a supply of 0.3 cub. ft.emulsion per minute under so a head of about 3 ft. to a 1 inch diameternearly horizontal pipe of about ft. in length dropping 3 ft., the airmay be supplied at about 2.5 cub. ft. per minute from the compressed airsupply. The tube may conveniently be made of rubber, with glass portionsif desired. Joints in the tube may be made with lead insertions.

It is found that as the turbulent flow of emulsion and air proceedsalong the horizontal or somewhat inclined tube, a surge develops which,I

when it has grown sufiiciently to occupy the cross section of the tube,will be followed at intervals by other similar surges, with interveningspaces which constitute in effect long air bubbles. These surges persistfor a long time in the advancing i emulsion, and maintain it as anemulsion over long distances. The formation of this kind oi flow doesnot depend on a supply of emulsion of such velocity that its how isturbulent in the absence of the air introduced therewith.

The invention is further illustrated by the dia-- grams attached hereto,of which Figure l. repre sents a vertical section of one form of anapparatus for putting the invention into effect, Figure 2 represents avertical section of another form of apparatus for putting the inventioninto sheet, and Figure 3 represents a vertical longitudinal section of aportion of transfer tube showing the alternation of surges of emulsionand air spaces that is caused to occur according to the invention.

fin Figure l, A represents the long transfer tube, which may be made ofrubber or lead. For convenience of representation it is shown broken inthe drawing. B represents a compressed air pipe leading from a sourceor" compressed air (not shown) into the tube, and. 0 represents acontrol valve for the compressed air. D represents an open feed vesselfor the emulsion through which the latter is supplied at the requiredrate from the source (not shown) through the pipe E. The lower part ofthe tube is of sufficient length to provide the necessary drivingpressure, and the upper portion is expanded into a deep funnel.

In Figure 2 the letters A, B and C have the same significance as inFigure l, and F represents a portion of the feed vessel which in this isa Washing apparatus in which the liquid nitric ester is maintained inemulsion with the aqueous liquid by means of air stirring. The portionof the apparatus containing the inlets for air and the liquids is notshown. In this case the air entering the feed vessel constitutes a.portion of the air entering the transfer tube, the remainder beingsupplied through the air inlet B.

In Figure 3, A represents a portion of the transfer tube through whichthe contents are passing in the direction shown by the arrow; H, Krepresents two surges of emulsion occupying the whole cross section ofthe tube; and L represents an intervening air space. .It will heobserved that the advancing surge leaves a considerable tail behind it,and that the drainings from each surge are taken up by the next oneadvancing.

In the foregoing detailed description of our invention it is apparentthat many variations in detail may be made-without departing from thespirit and scope thereof. We, therefore, intend to be limited only inaccordance with the following patent claims:

We claim:'

l. The method of transferring liquid explosive nitric esters, whichcomprises forming an aqueous emulsion with said explosive and forcingsaid emulsion through a conduit, alongwith an amount of air sufficientto cause turbulence.

2. The method of claim 1, wherein the liquid explosive nitric estercomprises nitroglycerin.

3. The method of claim 1, wherein the liquid. explosive nitric ester.comprises ethylene glycol dinitrate.

4. The method of transferring liquid explosive nitric esters, whichcomprises forming an aqueous emulsion with said explosive and forcingsaid emulsion through a conduit along with an amount of air sumcient tocause turbulence to prevent the separation of said emulsion into theconstituents thereof, part of said air being introduced into saidemulsion prior to the introduction of said emulsion into the conduit,and part being introduced into the conduit during the passage of theemulsion therethrough.

WIILIAM A. P. CHALLENOR. GORDON A. SCOTT.

